]> git.karo-electronics.de Git - linux-beck.git/commit
drm/i915/gen9: fix the WaWmMemoryReadLatency implementation
authorPaulo Zanoni <paulo.r.zanoni@intel.com>
Thu, 22 Sep 2016 21:00:30 +0000 (18:00 -0300)
committerJani Nikula <jani.nikula@intel.com>
Mon, 10 Oct 2016 13:06:38 +0000 (16:06 +0300)
commit4e4d3814a9bb4d71cd3ff0701d8d7041edefd8f0
treec8e12e1ff9185611ea5fd69ea29e9fb49471d7f3
parent17777d61f4a87d7b6d5585e8fdffa83773c594e7
drm/i915/gen9: fix the WaWmMemoryReadLatency implementation

Bspec says:
  "The mailbox response data may not account for memory read latency.
   If the mailbox response data for level 0 is 0us, add 2 microseconds
   to the result for each valid level."

This means we should only do the +2 in case wm[0] == 0, not always.

So split the sanitizing implementation from the WA implementation and
fix the WA implementation.

v2: Add Fixes tag (Maarten).

Fixes: 367294be7c25 ("drm/i915/gen9: Add 2us read latency to WM level")
Cc: stable@vger.kernel.org
Cc: Vandana Kannan <vandana.kannan@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1474578035-424-5-git-send-email-paulo.r.zanoni@intel.com
(cherry picked from commit 0727e40a48a1d08cf54ce2c01e120864b92e59bf)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
drivers/gpu/drm/i915/intel_pm.c